/*
 * Copyright (c) 2007-2012, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: ExsltCommon.java,v 1.2.4.1 2005/09/15 02:45:24 jeffsuttor Exp $
 */
package com.sun.org.apache.xalan.internal.lib;

import com.sun.org.apache.xalan.internal.extensions.ExpressionContext;
import com.sun.org.apache.xml.internal.dtm.DTMIterator;
import com.sun.org.apache.xml.internal.dtm.ref.DTMNodeIterator;
import com.sun.org.apache.xpath.internal.NodeSet;

/**
 * This class contains EXSLT common extension functions.
 * It is accessed by specifying a namespace URI as follows:
 * <pre>
 *    xmlns:exslt="http://exslt.org/common"
 * </pre>
 *
 * The documentation for each function has been copied from the relevant
 * EXSLT Implementer page.
 *
 * @see <a href="http://www.exslt.org/">EXSLT</a>
 * @xsl.usage general
 */
public class ExsltCommon {
    /**
     * The exsl:object-type function returns a string giving the type of the object passed
     * as the argument. The possible object types are: 'string', 'number', 'boolean',
     * 'node-set', 'RTF', or 'external'.
     *
     * Most XSLT object types can be coerced to each other without error. However, there are
     * certain coercions that raise errors, most importantly treating anything other than a
     * node set as a node set. Authors of utilities such as named templates or user-defined
     * extension functions may wish to give some flexibility in the parameter and argument values
     * that are accepted by the utility; the exsl:object-type function enables them to do so.
     *
     * The Xalan extensions MethodResolver converts 'object-type' to 'objectType'.
     *
     * @param obj The object to be typed.
     * @return objectType 'string', 'number', 'boolean', 'node-set', 'RTF', or 'external'.
     *
     * @see <a href="http://www.exslt.org/">EXSLT</a>
     */
    public static String objectType(Object obj) {
        if (obj instanceof String)
            return "string";
        else if (obj instanceof Boolean)
            return "boolean";
        else if (obj instanceof Number)
            return "number";
        else if (obj instanceof DTMNodeIterator) {
            DTMIterator dtmI = ((DTMNodeIterator) obj).getDTMIterator();
            if (dtmI instanceof com.sun.org.apache.xpath.internal.axes.RTFIterator)
                return "RTF";
            else
                return "node-set";
        } else
            return "unknown";
    }

    /**
     * The exsl:node-set function converts a result tree fragment (which is what you get
     * when you use the content of xsl:variable rather than its select attribute to give
     * a variable value) into a node set. This enables you to process the XML that you create
     * within a variable, and therefore do multi-step processing.
     *
     * You can also use this function to turn a string into a text node, which is helpful
     * if you want to pass a string to a function that only accepts a node set.
     *
     * The Xalan extensions MethodResolver converts 'node-set' to 'nodeSet'.
     *
     * @param myProcessor is passed in by the Xalan extension processor
     * @param rtf The result tree fragment to be converted to a node-set.
     *
     * @return node-set with the contents of the result tree fragment.
     *
     * Note: Already implemented in the xalan namespace as nodeset.
     *
     * @see <a href="http://www.exslt.org/">EXSLT</a>
     */
    public static NodeSet nodeSet(ExpressionContext myProcessor, Object rtf) {
        return Extensions.nodeset(myProcessor, rtf);
    }

}
